Information provision through contents, such as sounds, from numerous people, objects, services, and the like has been performed since the past. Sound is one-dimensional, time-series information. Therefore, when pieces of useful information are dispersed throughout a long passage, the user has to endure listening through uninteresting sections in wait for a piece of useful information to be played back.
In addition, in conventional information provision, a plurality of sounds are often multiplexed and outputted. However, when the plurality of sounds are simply multiplexed and outputted, the sounds are too overlapped and become indistinguishable. Therefore, for example, International Publication Pamphlet No. WO 2003/085511 discloses a technology in which a server delivers sound information and timing information, and sounds are outputted at timings that do not overlap. In addition, Japanese Laid-open Patent Publication No. 10-124292 discloses a method for simultaneously outputting a plurality of sounds that are localized in differing directions. Moreover, Japanese Laid-open Patent Publication No. 2002-023787 discloses a technology in which, when the playback timings of sounds overlap, the playback speed is increased depending on the number of sounds that are being played back and are awaiting playback. Furthermore, Japanese Laid-open Patent Publication No. 2005-070430 discusses a method for adjusting the sound pressure of words.